I

General military mansion.

The courtyard where Xiong Wencan was received is now used to receive important guests, and a maid is hired to clean it.

Six scholars came here today, including Xiao Shixuan, who are all mathematics lovers.

Since Xiao Shi was given the title of doctor of mathematics, and he was paid according to the salary of the county magistrate, everyone knew that Zhao Han attached great importance to mathematics. It is good at the top and effective at the bottom, and more and more people are learning mathematics.

However, most of the scholars are still at the elementary school mathematics level.

"Mr. Zhao!" The six scholars stood up in unison.

Zhao Han raised his hand with a smile: "Sit down."

After everyone sat down, they looked behind Zhao Han again, but it was Zhao Zhenfang who followed.

There is a blackboard in the middle of the yard, and everyone sits on chairs around the blackboard.

Zhao Han came to the blackboard and said, "You are all outstanding researchers in mathematics. I invite you to come today. The first thing is to establish a mathematics club. This math club is similar to the literature club. We usually exchange and discuss math problems. Everyone A quarterly "Mathematics" publication will be published to publish the achievements you have made in the near future. This year, the General Military Office allocated twenty taels of silver for the establishment and development of the Mathematics Society."

The six of them were quite happy, they were all different types of scholars, and they did not expect to be so valued by Zhao Han.

"The details of the Mathematics Association, you go down and discuss slowly," Zhao Han picked up the chalk made of chalk, "Today, I will talk about two things, one is logarithm, and the other is analytic geometry."

As a liberal arts student, Zhao Han had already forgotten almost all of his advanced mathematics, as well as many contents of junior high and high school.

Analytical geometry should be learned in junior high school, and logarithm is the knowledge of the first grade of high school. For these two things, Zhao Han only remembered the basics of the concepts, and had to rely on Xiao Shixuan and others to study them in depth.

Zhao Han couldn't wait any longer, he had to come up with the basic concepts, otherwise he would not be born in China until the Year of the Monkey.

Because logarithms and analytic geometry are very important, and they are key mathematical tools for the development of technologies such as astronomy, navigation, machinery, economy, and military affairs. In other words, it was the development of many fields such as astronomy, navigation, and machinery that forced the improvement of digital calculation methods, which gave birth to logarithm and analytic geometry in Europe.

Without these two mathematical tools, the development of astronomy, navigation, and machinery will reach a bottleneck and it will be difficult to break through.

Just this year, Descartes also came up with the concept of imaginary numbers.

China was far behind at this time, but the appearance of Zhao Han narrowed the gap. More than 90 years ago, the equal sign appeared in Europe, but it was not popularized until more than 40 years ago. 36 years ago, the greater than and less than symbols appeared in Europe; 6 years ago, the multiplication and division signs appeared in Europe; this year, Descartes used the root sign for the first time.

At least, the mathematicians under Zhao Han used the root sign earlier than European mathematicians.

Also this year, Descartes founded analytic geometry!

Zhao Han drew a cross coordinate system on the blackboard. The horizontal column marked the abbreviated symbol of "A", the vertical column marked the abbreviated symbol of "B", and the intersection point was marked as "0".

Did you suddenly have an impression?

That stuff is analytic geometry, and it was everywhere a few hundred years ago, but it's a novelty now.

Following Zhao Han's drawing with chalk stroke by stroke, the six scholars were both surprised and delighted, as if the door to a new world had been opened.

The more Zhao Zhenfang listened, the more confused she became, as if what was written on the blackboard were heavenly scriptures. She looked at the six people beside her, all of them paying attention, as if they all understood.

Zhao Zhenfang felt that she was so weak that she had to study mathematics hard in the future.

Because she thought it was boring, she asked her brother for an errand to do something in the math club. For example, helping to contact members, sorting out research results, editing quarterly mathematics journals, etc.

If she can't even understand other people's stuff, then how can she edit the school journal?

For one morning, Zhao Han only talked about the most basic things, mainly because he couldn't talk too deeply. Throwing down the chalk, he said, "Everyone stay for dinner, I have business in the afternoon. Farewell!"

"Congratulations to Mr. Zhao!"

The six people stood up and bowed in unison, and then no one went to eat, and all took out their small books to read.

"Did you understand?"

"I understand everything, it's like enlightenment."

"Especially the introduction of this variable is simply a stroke of genius, and many problems before can be easily solved!"

"Mr. Zhao is really a genius!"

"..."

The six sighed there, and then began to discuss.

In fact, the content they discussed was all mathematics in the third year of junior high school and the first year of high school, and it was relatively simple, and they were not qualified to do the big questions of the final exam.

Zhao Zhenfang jumped up and down and asked, "Second brother, can I learn mathematics from them in the future?"

"Okay, as long as you have something you like to do." Zhao Han said with a smile.

The two brothers and sisters stepped out of the gate, and a guard handed over a letter: "The farmers in the general town and Jianchang Mansion have also rioted. Zhao Bingyuan (Fei Ruhe) asked if he would send troops to take over."

Zhao Han also didn't care about eating, so he went back to the office first and asked the secretary to write a few transfer orders. He signed and stamped them with his own hand and sent them out before returning to the inner house.

There is also a vassal king in Jianchang Mansion, called King Yi, whose ancestor is the sixth son of Zhu Jianshen.

This department is quite famous, so it's not a big deal.

The first King Yi was very frugal, with few concubines, and his burial was simple. His eldest and second sons were equally frugal. The eldest son left no heirs, and passed the throne to the second son. The second son had five sons and asked for a reduction of 2000 shlumi.

But these five sons gave birth to eighty-six grandchildren!

By the time of Chongzhen, there were forty people in the Yiwang lineage only at the county level, and there were countless generals and lieutenants.

They do have a good reputation because they never make trouble, but the people of Jianchang Mansion don't think so. Here, like Raozhou Mansion, there was no whipping law, and Zhang Juzheng couldn't control Jianchang Mansion when he reformed.

This year, Jianchang Prefecture suffered from floods and droughts, and the Nanfeng sect banditry revived. The Southern Jiangxi Uprising next door is raging, and Fuzhou is also building a peasant association next door. How can the people of Jianchang Prefecture not follow suit?

Now, Nanfeng County is occupied by the Secret Esoteric Sect, and Fucheng is occupied by the peasant uprising army.

Mi Tanjiao also went to Guangchang County to preach. It will definitely be the number one enemy of the peasant association in the future. We must resolutely attack this kind of folk sect!

"Anything happened again? I just came to eat now." Fei Rulan asked with a smile.

Zhao Han said: "There is a mess in Jianchang Mansion, we must take it down in advance, otherwise I don't know how many people will die."

Fei Rulan said: "In the morning, Uncle Lin and Mrs. Ling came to visit, and they told Fei Chun about their marriage. They will get married at the end of the year, and the date has been chosen."

"Which family is the bride from?" Zhao Han asked casually.

Fei Rulan smiled and said: "I know you don't like to involve the big family. You are the daughter of an old master in the village school. I heard that she looks good and can read some words. The female celebrity is also doing very well. I don't know how many matchmakers come to the door."

"That kid is lucky." Zhao Han also laughed.

Fei Rulan suddenly said: "Rumei and Zhenfang have reached the age of marriage, shouldn't they think about it?"

Zhao Han shook his head and said, "There's no rush, you're only fifteen or sixteen years old, getting married too early can easily lead to dystocia."

"My mother is very anxious, she is already looking for Rumei's husband's family." Fei Rulan said.

Zhao Han smiled wryly: "Don't think about these things all day long, just find something else to do."

Fei Rulan said: "I have something to do. The teachers in Saomei Girls' School are all married talented women. I often correspond with them, chatting about literature, music and art."

Zhao Han thought for a while and said, "If you like, you can also go to a girls' school as a teacher."

"Can I do it too?" Fei Rulan's eyes sparkled.

Zhao Han said: "If you are too busy, you can only go for half a day. You will be at home in the morning and be a teacher in the afternoon."

"That's great!" Fei Rulan cheered up, and immediately cheered, as if she had returned to her girlhood.

Zhao Han always felt that Fei Rulan was a little bored, most of them were idle at home, and it would be fine to go out and do things in the future. If he really takes over the world in the future, I'm afraid it will be difficult to go out, and he will definitely be opposed by the officials.

After lunch, Zhao Han held Fei Rulan in his arms, took a nap for a while, stretched his waist and continued to work.

Before processing a few official documents, the secretary sent information: North Korea surrendered to the Qing Dynasty.

During the first month of the lunar year, Huang Taiji sent troops to North Korea, all the way to the city of Pyongyang. The king of Joseon was terrified, and fled to Namhansan with his eldest son and his officials, while his second son and his royal family took refuge in Ganghwa Island.

The Ming army got the news in February and went to sea for rescue in March. Before the reinforcements arrived, they received the news that North Korea had surrendered to the Qing Dynasty.

This year, the whole country is in a mess, there are bandits everywhere, North Korea's surrender did not cause any disturbances, and Zhao Han didn't receive the news until now.

Zhao Han called Pang Chunlai and Li Banghua, and took out the secret letter from North Korea to the Qing Dynasty.

Pang Chunlai frowned and said, "Da Ming is in danger."

"The whole territory of Jiangxi must be occupied in advance." Li Banghua suggested.

A few years ago, the Manchu Qing had surrendered Mongolia, and now they have surrendered North Korea. It means that there are no constraints on the left and right, and you can attack Daming with all your strength in the future, and it will definitely be more fierce every time!

Both Pang Chunlai and Li Banghua panicked, fearing that Beijing would not be able to hold on.

Really, the situation this year is too scary, most of China has suffered disasters. The drought in Nanzhili and Zhejiang dealt the heaviest blow to Chongzhen, and its influence far exceeded that of Zhao Han's uprising in Jiangxi.

Daming's taxes are all supported by Nanzhili and Zhejiang!

Zhao Han said: "Jianchang Prefecture was occupied by rebels, and Nanfeng County was stolen by religious bandits. I have ordered the army, officials and peasant associations to take action in advance."

"It should be like this," Li Banghua said, "This year we must take all of Jianchang, Fuzhou, and Raozhou. In this way, there will only be Nankang, Jiujiang, and Guangxin in Jiangxi. We will strive to occupy the whole of Jiangxi after the summer harvest next year." territory."

"I agree with this strategy." Pang Chunlai immediately agreed.

Pang Chunlai is from Liaodong, and he knows how cruel the Tartars are. North Korea's surrender made Pang Chunlai feel a sense of crisis, fearing that one day the Tartars would suddenly capture Beijing.

At that time, if Chongzhen moved south and ruled with the Tartars, Jiangxi would become a thorn in the court's side.

It is necessary to occupy Jiangxi as soon as possible, and then take Fujian, Guangdong and southern Huguang, so that Chongzhen will definitely not dare to go to the south.